simple-signal

Easy signalling for simple-peer using socket.io.

Features

• Streamlines WebRTC signaling without losing any flexibility.
• Exposes the entire simple-peer API.
• Useful for managing multiple connections.
• Uses modern async/await.

Install

Server:

npm install simple-signal-server --save

Client (with Browserify):

npm install simple-signal-client --save

Without Browserify, use simple-signal-client.min.js.

Example

A common signaling scheme is to connect two clients by having one client "call" the ID of another.

Server:

const signalServer = require('simple-signal-server')(io)
const allIDs = new Set()

signalServer.on('discover', (request) => {
  const clientID = request.socket.id // clients are uniquely identified by socket.id
  allIDs.add(clientID) // keep track of all connected peers
  request.discover(Array.from(allIDs)) // respond with id and list of other peers
})

signalServer.on('disconnect', (socket) => {
  const clientID = socket.id
  allIDs.delete(clientID)
})

signalServer.on('request', (request) => {
  request.forward() // forward all requests to connect
})

Client:

var signalClient = new SimpleSignalClient(socket) // Uses an existing socket.io-client instance

signalClient.on('discover', async (allIDs) => {
  const id = await promptUserForID(allIDs) // Have the user choose an ID to connect to
  const { peer } = await signalClient.connect(id) // connect to target client
  peer // this is a fully-signaled simple-peer object (initiator side)
})

signalClient.on('request', async (request) => {
  const { peer } = await request.accept() // Accept the incoming request
  peer // this is a fully-signaled simple-peer object (non-initiator side)
})

signalClient.discover()

Client API

signalClient = new SignalClient(socket, [options])

Create a new signalling client.

Required socket is a socket.io-client instance.

Options:

• connectionTimeout: number = 10000: Defines the time to wait to establish a connection.

signalClient.id

The identifying string for this client's socket. null until discovery completes.

signalClient.discover(discoveryData)

Initiate discovery.

discoveryData is any discovery data to be sent to the server.

{ peer, metadata } = await signalClient.connect(id, [metadata], [peerOptions])

Request to connect to another client. Returns a Promise.

id is the signalClient.id of the other client.

Optional metadata is any serializable object to be passed along with the request.

Optional peerOptions are the options to be passed to the SimplePeer constructor.

signalClient.on('discover', function (discoveryData) {})

Fired when the client has connected to the server and done discovery.

discoveryData is any additional data that has been passed by the server.

signalClient.on('request', function (request) {})

Fired on receiving a request to connect from another client.

request.initiator

The id of the remote client's socket.

request.metadata

Any additional metadata passed by the requesting client or server.

{ peer, metadata } = await request.accept([metadata], [peerOptions])

Accept the request to connect. Not calling this method will ignore the request. Returns a Promise.

metadata is any serializable object to be passed along with the answer.

peerOptions are the options to be passed to the SimplePeer constructor.

Promise will reject if the other side calls reject().

request.reject([metadata])

Rejects the request to connect. Not calling this method will ignore the request.

metadata is any serializable object to be passed along with the rejection.

signalClient.peers()

List all currently connecting/connected peers. Returns an array of SimplePeer objects.

Server API

signalServer = require('simple-signal-server')(io)

Create a new signalling server.

Required io is a socket.io instance.

signalServer.on('discover', function (request) {})

Optional listener allows you to return additional discovery data when a new client connects or rediscovers.

request.socket

The socket.io socket used by the client initiating discovery.

request.discoveryData

Any additional data passed by the discovering client. A good place for credentials.

request.discover([discoveryData])

Allow discovery to continue. Listening to "discover" and not calling this method will block discovery.

Optional discoveryData is any serializable object to be passed along with the discovery response. A good place for credentials.

signalServer.on('request', function (request) {})

Optional listener allows you to filter connection requests on the server.

request.initiator

id of the socket used by the client initiating the request.

request.target

id of the socket used by the client that will receive the request.

request.metadata

Any additional metadata passed by the requesting client.

request.forward([metadata])

Allow the request to continue. Listening to "request" and not calling this method will block the request.

Optional metadata is any serializable object to be passed along with the request.

signalServer.on('disconnect', function (socket) {})

Listens to disconnected sockets. Similar to the socket.io disconnect event, but only fires for clients that completed discovery.

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